Seed oils such as sunflower, grapeseed, canola, and corn—key ingredients in many processed Western diets—might contribute to the rise in colon cancer, according to a new U.S. government-led study.
These oils could trigger chronic inflammation in the body, a condition that fosters tumor growth. While past research was inconclusive, this groundbreaking study sheds new light on the connection.
Researchers analyzed tumors from over 80 colon cancer patients aged 30 to 85. The results revealed elevated levels of bioactive lipids—oily molecules created when the body metabolizes seed oils—inside the tumors. These lipids not only increase inflammation but also interfere with the body’s natural ability to heal, creating a more favorable environment for cancer to grow.
In contrast, healthier oils rich in omega-3 fatty acids, such as those found in avocados and olives, can help reduce inflammation, the study suggested.
Dr. Timothy Yeatman, a prominent physician-scientist and associate director at the TGH Cancer Institute, stressed the importance of rethinking Western dietary habits. “Unhealthy diets are well-known to cause inflammation in the body,” he explained. “Now, we see this inflammation in colon tumors. Poor eating habits, especially heavy consumption of ultra-processed foods and inflammatory seed oils, weaken the immune system and impair the body’s ability to heal.”
Describing cancer as a “chronic wound that won’t heal,” Dr. Yeatman warned that a diet dominated by processed foods exacerbates this condition.
Despite these findings, leading U.S. health organizations have clarified that consuming seed oils in moderation as part of a balanced diet has not been directly linked to cancer.
Published in the medical journal Gut, the study contributes to growing evidence that diet plays a critical role in preventing chronic diseases, including cancer.
